The effectiveness of fibrinolytic treatment has been shown in cases of thoracic empyema in adults. In pediatric patients experience is, however, very limited. The aim of this study was to determine the success and complication rates of fibrinolytic treatment in thoracic empyema in children. A series of 25 consecutive children who had loculated pleural empyemas that did not respond to tube thoracostomy and antibiotics is presented. Their ages ranged from 1 to 12 years (mean 4.2). There were 19 boys and 6 girls, and all epyemas were postpneumonic. The fibrinolytic agent used was urokinase in 17 and streptokinase in 8. The mean duration of fibrinolytic treatment was 4.3 days (range 2 to 8) and the mean duration of chest-tube drainage was 8.9 days (range 7 to 13). In 20 patients the fluid output from the chest tube increased significantly after instillation of the fibrinolytic agent, and these patients showed almost complete resolution of the effusion on chest radiograph and ultrasound examinations (80%). Only 5 patients developed complications: bronchopleural fistula and pleural thickening in 3, and recurrent effusion, multiloculation, and pleural thickening in other 2 which were managed by surgical intervention (20%). Our study suggests that intrapleural fibrinolytic treatment is an effective and safe adjunctive therapy in children with thoracic empyema and can obviate a thoracotomy in most cases.